Type bed gib



July 25, 1939. s.. A. HUFFMAN TYPE BED GIB n a m @SHN mm a N e l l m @NlWN QN QN QN QN. d 1 P QU LTL Patented- July 25, 1939 UNITED STATESPATENT OFFICE TYPE BED GIB Application April 16, 1937, Serial No.137,238

4 Claims.

This invention relates generally to printingA presses, and in particularto an arrangement of gibs for guiding a reciprocating flat bed back andforth along the frame of the press. When it is atempted tooperate'reciprocating fiat bed presses at high speeds, the mass of thebed imposes rather denite limits on the speeds which it is possible toattain. As a result, the use of beds composed of relatively lightnon-ferrous metals or alloys is indicated, in contrast to the Acast-ironbeds previously employed. This expedient, however, introduces furthercomplications. Non-ferrous metals and alloys generally have a highercoefficient of thermal expansion than cast iron. Thismeans that runningclearances between an alloy bed and a cast-ironl frame, which aresatisfactory at one temperature, are either too small or too great atother temperatures. Relatively close clearances are desirable 201Y atall times, in order to insure accurate register, and the'expansion of analloy bed between its idle temperature and its operating temperature mayexceed this clearance considerably.

I have invented an arrangement of gibs for 25l-printing-press bedswhereby the proper spacing of the gibs relative to the way-frames of thepress is maintained at all times, regardless of changes in thetemperature of the various parts. This permits the use of beds of lightnon-ferrous metals or alloys, and the maintenance of the proper runningclearances at all temperatures without the necessity for any adjustmentor resetting. In accordance with my invention, I provide a bed withgibs, at least one of which is movable through a short distancetransversely of the bed. I also provide means for spacing the movablegib from the other gib by means, such as a spacer bar or rod, which iscomposed of material having substantially the same coefficient ofthermal expansion as the material of which the press frame is composed.The spacing of the gibs is thus maintained by means independent of thebed so that expansion or contraction of the latter does not change theclearance between 45 the gibs and the Way-frames.

For a complete understanding of the invention, the following detaileddescription may be referred to in connection with the accompanyingdrawing illustrating a preferred embodiment. In the drawing,

Fig. 1 is a partial plan view of a press bed and the way-frames on whichit reciprocates;

Fig. 2 is a transverse sectional view along the line II-II of Fig. 1;and

Fig. 3 is a partial longitudinal sectional view along the line III-IIIof Fig. 1.

The press bed, indicated at I0, is of ribbed construction and may becomposed of any suitable material, such as a relatively light non- 5ferrous alloy. Side and intermediate races II and I2 having hardenedWearing surfaces I3 rest on roller bearings I4. These bearings travelalong races I5 formed in the Way-frame IE and having hardened wearingsurfaces Il. The Wayl0 frame i6 is provided with tracks I8. Gibs I9 and23 cooperate with the tracks I8. It will be understood that the gibs I9and 2li-are duplicated at the opposite end of the bed,V which does notappear in the drawing.

The gib I9 is simply a block having a shoulder 2I for engaging under thetrack I 8. The gib is secured to the bed by cap screws 22. Its positionon the bed is precisely fixed, furthermore, by

dowels 23 extending into holes formed in the gibV 2l)` and the bed.

The gib 20 differs slightly from the gib I9 in that it is keyed to thebedat 24' for sliding movement transversely thereof. The gib 20,` ofcourse,

has a shoulder 2I cooperating with the track I8 25' in the same manneras the gib I9;

The gib 201s movably supported on" the bed Iii by cap screws25havingreduced end portions 26. The gib 20 is bored at2'I to receive thecap screws 25, the diameter of the bores 21 being 30 slightly greaterthan that ofthe screws -25 whereby slight movement of the gib 2Btransversely of the bed is permitted.

A thrust bar or spacer rod 28 has a reduced end 23 extending into an eye36 formed integral 35 with the gib 2G'. The bar 28 extends transverselyof the bed I, and the end thereof remote from the eye 38 is threadedthrough a tapped hole in a peripheral iangev 3l depending from thesurface of the bed. A lock nut 32 permits the bar 40 28 to be held inposition when properly adjusted. The bar 23 is preferably of steel orsome other material having substantially the same coeffi-A cient ofthermal expansion as the material of which the way-frame is composed,usually cast 45 iron. The gib 20 will be initially adjusted by turningthe bar 28, to provide the proper clearances between the shoulder 2I onthe gibs and the tracks I8 on the way-frame. The end of the bar 28extending through the ange SI is squared 50 to take a wrench for thispurpose. When the proper adjustment of the gib 2D has been made, thelock nut 32 is tightened. The running clearances between the gibs andthe tracks initially provided are maintained at all times, regardless 55of temperature changes and the. diierence between the coemcient ofthermal expansion of the Vbed Iii and the frame I6. If the press isstarted.

While relatively cold as, for example, after a period of idleness, thetemperature of the parts. Will increase as the operation of the pressycontinues. The bed I0 will expand a greater amount than the frame I6. Nodifficulty is experienced as a result of this expansion, since the raceslland l2 are free to shift relative to the roller bearings I4. The bar28 expands at about the same rate as the way-frame I6, and thus keepsgib 2l) up against its track with the initially chosen runningclearance, at all times. When operation of the press ceases, contractionof the frame i6 on cooling is substantially equaled by contraction ofthe bar 28 whereby a free running t between the gib 2l) and its track ismaintained'. It will be understood that the screws 25 are not tightenedsuiiciently to prevent lateral adjusting movement of the gib 2l)relative to the bed I0.

It will be `clear from the foregoing description that the inventionobvates an objection to the use of beds of nen-ferrous metals or alloyswhich has existed heretofore, since it provides means While I havedescribed the invention as ap-` plied to the reciprocating beds ofprinting presses, it will be understood that it may be otherwise appliedand utilized. Changes in the exact construction disclosed, furthermore,may be made without departing from the spirit of the invention or thescope of the appended claims.

I claim: Y

l. Means for maintaining a close running fit between the Way-frame of aprinting press and a bed reciprocable thereon composed of materialhaving a thermal coefficient of expansion different from that of thematerial of which the frame is composed, comprising a gib ixedly mountedadjacent one side of. said bed, a second gib movably mounted adjacentthe other side of said frame, said gibs cooperating With said frame toguide movement of the bed thereover, and a thrust bar composed ofmaterial having a thermal. coefficient of expansion substantially thesame as that of the material of which the frame is composed andextending across the bed, for holding the movable gib in a predeterminedposition relative to the side of the frame.l

2. Means for maintaining a close running lit between guideways on aframe and. a member reciprocable thereon composed of material having athermal ooeicient of expansion different from that of. the material ofwhich the frame is composed, comprising a gib xedly mounted adr jacentone side of said member, a second gib movably mounted adjacent the otherside of said member, said gibs cooperating with said guideways to guidemovement of said member thereover, and a spacer mounted for expansionand contraction independently of said member for maintaining the movablegib in the desired position relative to the fixed gib, said spacer beingcomposed of material having a thermal coefficient of expansionsubstantially the same as that of the material of which the frame iscomposed.

3. Means for maintainingy a close running fit between a frame having atleast a pair of Ways thereon and a bed reciprocably supported on saidWays, said frame and bed being composed of materials having differentcoefficients of thermal expansion, said means including a gib xed`relative to said bed and cooperating with Vone of. said Ways, a gibmovably mounted on said bed cooperating with another of said Ways, andmeans positioning said last-mentioned gib relative to the bed inaccordance with the expansion and contraction of said frame, regardlessof the expansion and contraction of said bed.

4. Means for maintaining a close running iit between a frame having atleast a pair of yWays thereon and a bed reciprocably supported on saidWays, said frame and bed being composed of materials having differentcoeiiicients of thermal expansion, said means including gibscooperatingA with the ways and so mounted on the bed as to permitrelative movement between said gibs, and means for positioning the gibsWith relation to each other in accordance with the expansion .andY

contraction of said frame, regardless of the expansion and contractionof said bed.

SAMUEL A. HUFFMAN.

